JPS6375385A - Axial thrust balancing apparatus for pump - Google Patents
Axial thrust balancing apparatus for pumpInfo
- Publication number
- JPS6375385A JPS6375385A JP21949486A JP21949486A JPS6375385A JP S6375385 A JPS6375385 A JP S6375385A JP 21949486 A JP21949486 A JP 21949486A JP 21949486 A JP21949486 A JP 21949486A JP S6375385 A JPS6375385 A JP S6375385A
- Authority
- JP
- Japan
- Prior art keywords
- balance
- suction pipe
- pipe
- protrusion
- suction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 6
- 230000002441 reversible effect Effects 0.000 claims abstract description 5
- 238000007789 sealing Methods 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 230000000694 effects Effects 0.000 abstract description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000000725 suspension Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Landscapes
- Control Of Non-Positive-Displacement Pumps (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、バランス管を用いたポンプの軸推力平衡装置
に係り、特に低流量域における軸推力上昇を抑えるのに
好適な軸推力平衡装置に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pump axial thrust balancing device using a balance tube, and is particularly suitable for suppressing an increase in axial thrust in a low flow region. Regarding.
ポンプの軸推力平衡装置の一つとして、一般的にインペ
ラ背面のつり合い室と吸込管をバランス管にて接続し、
つり合室の圧力を吸込圧力まで下げ軸推力を低減させる
方法がよく用いられる。しかし文献「ターボ機械の低流
量域特性に関する調査報告書（日本機械学会誌６９，５
６８．（１９６６−５）５７５頁）」に記載されている
ように低流量域においてはインペラ入口付近に逆流が生
じ、これが軸推力に影響し、低流量域で軸推力が急増す
る欠点があった。As one of the pump's axial thrust balancing devices, the balance chamber on the back of the impeller and the suction pipe are generally connected with a balance pipe.
A method often used is to reduce the pressure in the balance chamber to the suction pressure to reduce the axial thrust. However, the document “Research Report on Low Flow Region Characteristics of Turbomachinery (Journal of Japan Society of Mechanical Engineers 69, 5
68. (1966-5, p. 575), a backflow occurs near the impeller inlet in the low flow rate region, and this affects the axial thrust, resulting in a drawback that the axial thrust rapidly increases in the low flow rate region.
上記従来技術は低流′ｊｉ運転時、吸込管に旋回を伴な
った逆流が生じ、この旋回による遠心力のために管の外
側に向って静圧が高くなることによりつり含窒の圧力も
高くなり結局軸推力が上昇する問題があった。In the above-mentioned conventional technology, during low-flow operation, a backflow accompanied by swirling occurs in the suction pipe, and the centrifugal force caused by this swirling causes the static pressure to increase toward the outside of the pipe, causing the pressure of suspended nitrogen to increase. There was a problem in that the shaft thrust became higher and the axial thrust eventually increased.
本発明の目的は、低流量運転時においても、軸推力上昇
のないポンプの軸推力平衡装置を得ることにある。An object of the present invention is to obtain a pump axial thrust balancing device that does not cause an increase in axial thrust even during low flow rate operation.
上記目的を達成するため１本発明は、インペラ後面シュ
ラウドの封水隙間より小径部とそれと相対するケーシン
グの面との間に形成したつり含窒と吸込管とをバランス
管により接続した片吸込遠心ポンプの軸推力平衡装置に
おいて、バランス管の吸込管への開口部に近接して、低
流量域でのインペラからの逆流による旋回流を防止する
ために吸込管壁に、バランス管が臨む部分よりも旋回方
向上流側に旋回流の旋回方向に直角な突起を設けたこと
を特徴とするものである。In order to achieve the above objects, the present invention provides a single suction centrifuge in which a suspension tube formed between a portion smaller in diameter than the water sealing gap of an impeller rear shroud and a surface of a casing facing it and a suction tube is connected by a balance tube. In a pump's axial thrust balance device, a part of the balance pipe facing the suction pipe wall is installed near the opening of the balance pipe to the suction pipe to prevent swirling flow due to backflow from the impeller in the low flow area. This is also characterized in that a protrusion perpendicular to the swirling direction of the swirling flow is provided on the upstream side in the swirling direction.
吸込管に取付けた突起は、管内の旋回流をせき止め、背
後の管壁部に旋回流が剥離した低圧部を形成する。又突
起により旋回流自体が弱められる。The protrusion attached to the suction pipe dams up the swirling flow inside the pipe, and forms a low-pressure part where the swirling flow is separated on the back wall of the pipe. Furthermore, the swirling flow itself is weakened by the protrusion.
従がって、バランス管の吸込管への開口部に近接して、
前記逆流による旋回流の上流側に前記突起を設けること
により、バランス管が突起背後の低圧部に接続される。Therefore, in close proximity to the opening of the balance pipe to the suction pipe,
By providing the protrusion on the upstream side of the swirling flow caused by the counterflow, the balance pipe is connected to the low pressure section behind the protrusion.
よって、この低圧部とつり含窒がバランス管によって平
衡され、低流量域においても軸推力の上昇を抑えること
ができる。Therefore, this low pressure section and the suspension nitrogen content are balanced by the balance tube, and an increase in axial thrust can be suppressed even in a low flow rate region.
本発明は、低流量時における吸込管内の効流の影響が、
バランス管の開口部に及ばないようにしたものである。In the present invention, the influence of the effective flow in the suction pipe at low flow rates is
It is designed so that it does not reach the opening of the balance tube.
ポンプの流量を設計流量より減少させてゆくとインペラ
入口より流体の逆流が生ずるが、この逆流は、インペラ
の回転方向の強い円周速度成分を持っているため、遠心
力の作用で吸込管の外側に向って静圧が高くなる。この
圧力の影響を受けてつり含窒の圧力が高くなり、軸推力
が上昇する。When the pump flow rate is reduced from the design flow rate, a backflow of fluid occurs from the impeller inlet, but since this backflow has a strong circumferential velocity component in the direction of rotation of the impeller, the suction pipe is affected by the action of centrifugal force. Static pressure increases toward the outside. Under the influence of this pressure, the pressure of the suspended nitrogen increases, and the axial thrust increases.
これを防ぐために第２図に示すように、吸込管のバラン
ス管の開口部近くにおいて、旋回流の上流側に突起を設
け、吸込管壁近くの流体の流れを変え、バランス管開口
部に低圧部を発生させるようにしたものである。In order to prevent this, as shown in Figure 2, a protrusion is provided on the upstream side of the swirling flow near the opening of the balance pipe of the suction pipe to change the flow of fluid near the suction pipe wall and lower the pressure at the opening of the balance pipe. The system is designed to generate parts.
以下、本発明の具体的実施例を第１図〜第５図により説
明する。第１図は支軸の片吸込遠心ポンプの断面図で、
ケーシング１内には回転軸２により回転駆動されるイン
ペラ３を収納しである。Hereinafter, specific embodiments of the present invention will be described with reference to FIGS. 1 to 5. Figure 1 is a cross-sectional view of a single-suction centrifugal pump with a spindle.
An impeller 3 rotatably driven by a rotating shaft 2 is housed within the casing 1 .
前記インペラの前面シュラウド３ａの吸込口部の外側に
は、前記前面シュラウドとケーシングとの間に環状の封
水隙間Ｃを設けである。また、後面シュラウド３ｂとケ
ーシング１との間にも、前記前面シュラウド３ａの封水
隙間と同一半径上に環状の封水隙間Ｃ′が設けてあり、
それより小径側の後面シュラウドと、それと相対するケ
ーシング面１ａとの間に形成したつり含窒ｄと、吸込室
４との間をバランス管５により接続しである。そして、
第１図及び第２図に示すように、このバランス管５の吸
込管における開口部に近接して、羽根車の回転方向に対
し逆側の吸込管壁に突起６が設けである。An annular water-sealing gap C is provided between the front shroud and the casing on the outside of the suction port of the front shroud 3a of the impeller. Also, an annular water sealing gap C' is provided between the rear shroud 3b and the casing 1 on the same radius as the water sealing gap of the front shroud 3a,
A balance pipe 5 connects the suction chamber 4 to the suspension nitrogen-containing d formed between the rear shroud on the smaller diameter side and the casing surface 1a facing it. and,
As shown in FIGS. 1 and 2, a protrusion 6 is provided on the suction pipe wall on the opposite side with respect to the rotational direction of the impeller, close to the opening in the suction pipe of the balance pipe 5.
上記のように構成した装置の作用について説明する０回
転軸によりインペラ３が回転すると液体は吸込管４から
インペラへ吸込まれる。そしてインペラにより昇圧され
た後ケーシング内の流路を経て吐出し、高圧液体にして
揚液する。インペラより吐出した高圧液体の一部は、イ
ンペラの後面シュラウド３ｂとケーシングとの間の封水
隙間ｃ′、つり含窒ｄ及びバランス管５を介して吸込管
４に漏洩するが、封水隙間Ｃ′は可及的に僅少な隙間と
しているため、漏洩液の圧力低下はほとんどこの封水隙
間にて生ずる。従って、つり令室ｄ内の圧力は吸込管４
内の圧力とほぼ等しくなり、これにより軸推力がバラン
スし、軸受７に加わる荷重は小さい。ところで、ポンプ
運転流量を設計点より減少して行くと、第１図及び第２
図の矢印で示すように、インペラより吸込側に向う逆流
が生ずるが、この逆流はインペラの回転方向の強い旋回
成分を有する。従って、前記逆流が生ずると旋回流れに
よる遠心力の作用により吸込管の管壁近くの圧力が吸込
管断面の平均圧力より高くなるが、本発明は突起６によ
り前記旋回流れをせき止め、その背後の管壁部に、第３
図に示すように低圧部を生ずるようにしている。前記バ
ランス管は、この低圧部に接続しているため、インペラ
３からの逆流が生じても、バランス管５内及びつり令室
ｄ内の圧力上昇は生じない、従って、インペラ入口逆流
の発生に伴う軸推力の増大を防止できる。The operation of the apparatus configured as described above will be explained. When the impeller 3 rotates by the zero rotation axis, liquid is sucked into the impeller from the suction pipe 4. After being pressurized by an impeller, it is discharged through a flow path in the casing to form a high-pressure liquid and pump it. A part of the high-pressure liquid discharged from the impeller leaks to the suction pipe 4 via the sealing gap c' between the impeller's rear shroud 3b and the casing, the suspension nitrogen-containing d, and the balance pipe 5. Since C' is made as small as possible, most of the pressure drop of the leaked liquid occurs in this sealing gap. Therefore, the pressure inside the suspension chamber d is
As a result, the axial thrust is balanced and the load applied to the bearing 7 is small. By the way, when the pump operating flow rate is decreased from the design point, the results shown in Figures 1 and 2
As shown by the arrow in the figure, a backflow is generated from the impeller toward the suction side, and this backflow has a strong swirling component in the direction of rotation of the impeller. Therefore, when the reverse flow occurs, the pressure near the wall of the suction pipe becomes higher than the average pressure in the cross section of the suction pipe due to the action of centrifugal force due to the swirling flow. On the pipe wall, the third
As shown in the figure, a low pressure area is created. Since the balance pipe is connected to this low pressure section, even if backflow occurs from the impeller 3, no pressure rise will occur in the balance pipe 5 and the suspension chamber d.Therefore, the occurrence of backflow at the impeller inlet will not occur. This can prevent the accompanying increase in axial thrust.
さて、前記突起は逆流による旋回流をせき止め旋回流れ
を弱める作用があるが、このように吸込管内の逆流によ
る旋回流れを突起等により止めると、第４図の破線で示
すように締切点近くの全揚遍及び軸動力が増大すること
が知られている。締切揚程が増大すればケーシングや吐
出配管の許容圧力を高める必要があり高価となる。この
ため、上記突起６の高さは可及的に低くして旋回流を止
める作用を小さくすることが好ましい、第３図に示すよ
うな突起６により剥離した旋回流は、その下流で再び壁
面に付着し、その間で低圧部が形成されるが、この低圧
部にバランス管の開口部を接続すること及び締切点特性
への影響を小さく抑えることを考慮すると、前記突起６
の高さｈはバランス管５の開口部の内径りに対しｄ／１
０≦ｈ≦ｄ／２に選ぶことが望ましい。Now, the protrusion has the effect of blocking the swirling flow caused by the backflow and weakening the swirling flow, but if the swirling flow caused by the backflow in the suction pipe is stopped by the protrusion, etc., as shown by the broken line in Fig. It is known that total lift and shaft power increase. If the cut-off head increases, it is necessary to increase the allowable pressure of the casing and discharge piping, which becomes expensive. For this reason, it is preferable to reduce the height of the protrusion 6 as much as possible to reduce the effect of stopping the swirling flow.The swirling flow separated by the protrusion 6 as shown in FIG. A low-pressure part is formed between the protrusions 6 and 6. Considering that the opening of the balance pipe is connected to this low-pressure part and that the influence on the cut-off point characteristics is kept small, the protrusion 6
The height h is d/1 with respect to the inner diameter of the opening of the balance tube 5.
It is desirable to select 0≦h≦d/2.
なお、突起６により旋回流れがせき止められ。Note that the protrusion 6 blocks the swirling flow.
旋回速度が減するのを小さくするため、第５図に示すよ
うに逆流による旋回流れと接する突８６の面を、傾斜面
６ａとしてもよい。In order to reduce the decrease in swirling speed, the surface of the protrusion 86 that comes into contact with the swirling flow caused by the reverse flow may be formed into an inclined surface 6a, as shown in FIG.
以上に述べたように、本発明によれば、ポンプの低流量
運転時に生ずる吸込口での逆流による圧力上昇の影響を
バランス管に与えないようにできるので、低流量運転時
の軸推力上昇を防止できる効果がある。As described above, according to the present invention, it is possible to prevent the balance pipe from being affected by the pressure increase due to backflow at the suction port that occurs during low flow rate operation of the pump. It has a preventive effect.
第１図は本発明の一実施例の車軸片吸込遠心ポンプの断
面図、第２図は第１図の■−■線断面図、第３図は吸込
管に突起を設けたことにより生ずる吸込管壁の圧力分布
を示す図、第４図は突起を大きくした場合のポンプ性能
に与える影響を示す線図、第５図は本発明の他の実施例
を示す要部断面図である。
１・・・ケーシング、２・・・軸、３・・・インペラ、
３ ａ −前面シュラウド、３ｂ・・・後面シュラウド
、４・・・吸込管、５・・・バランス管、６・・・突起
、Ｃ・・・封水隙間、Ｃ′・・・封水隙間、ｄ・・・っ
り含窒、７・・・軸封部、８・・・軸受部。Fig. 1 is a sectional view of an axle single suction centrifugal pump according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line FIG. 4 is a diagram showing the pressure distribution on the pipe wall, FIG. 4 is a diagram showing the effect of increasing the size of the protrusion on pump performance, and FIG. 5 is a cross-sectional view of main parts showing another embodiment of the present invention. 1...Casing, 2...Shaft, 3...Impeller,
3 a - Front shroud, 3b... Rear shroud, 4... Suction pipe, 5... Balance pipe, 6... Protrusion, C... Water sealing gap, C'... Water sealing gap, d...Thick nitrogen-containing, 7...Shaft sealing part, 8...Bearing part.
Claims (1)
れと相対するケーシングの面との間に形成したつり合室
と吸込管とをバランス管により接続した片吸込遠心ポン
プの軸推力平衡装置において、バランス管の吸込管への
開口部に近接して、低流量域でのインペラからの逆流に
よる旋回流を防止するために吸込管壁に、バランス管が
臨む部分よりも旋回方向上流側に旋回流の旋回方向に直
角な突起を設けたことを特徴とするポンプの軸推力平衡
装置。 ２、特許請求の範囲第１項において、前記バランス管の
吸込管への開口部の内径をｄ、前記突起の高さをｈとす
るときｄ／１０≦ｈ≦ｄ／２となるように突起の高さを
定めたことを特徴とするポンプの軸推力平衡装置。 ３、特許請求の範囲第１項において、前記突起の前記逆
流による旋回流と接する面を、突起の吸込管壁位置が突
起先端より前記旋回流の上流側となるように傾斜させた
ことを特徴とするポンプの軸推力平衡装置。[Claims] 1. A shaft of a single-suction centrifugal pump in which a suction pipe is connected to a balance chamber formed between a portion smaller in diameter than the water sealing gap of the rear shroud of an impeller and a surface of a casing facing the same through a balance tube. In a thrust balancing device, in order to prevent swirling flow due to reverse flow from the impeller in a low flow region, a part of the suction pipe near the opening of the balance pipe to the suction pipe is placed on the suction pipe wall in the direction of rotation than the part facing the balance pipe. An axial thrust balance device for a pump, characterized in that a protrusion is provided on the upstream side at a right angle to the swirling direction of the swirling flow. 2. In claim 1, the protrusion is such that d/10≦h≦d/2, where d is the inner diameter of the opening of the balance pipe to the suction pipe, and h is the height of the protrusion. An axial thrust balancing device for a pump, characterized in that the height of the pump is determined. 3. Claim 1 is characterized in that the surface of the protrusion in contact with the swirling flow due to the reverse flow is inclined such that the suction pipe wall position of the protrusion is on the upstream side of the swirling flow than the tip of the protrusion. Axial thrust balance device for pumps.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21949486A JPS6375385A (en) | 1986-09-19 | 1986-09-19 | Axial thrust balancing apparatus for pump |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21949486A JPS6375385A (en) | 1986-09-19 | 1986-09-19 | Axial thrust balancing apparatus for pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6375385A true JPS6375385A (en) | 1988-04-05 |
Family
ID=16736327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21949486A Pending JPS6375385A (en) | 1986-09-19 | 1986-09-19 | Axial thrust balancing apparatus for pump |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6375385A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02291497A (en) * | 1989-02-10 | 1990-12-03 | Kubota Corp | Vertical shaft pump |
-
1986
- 1986-09-19 JP JP21949486A patent/JPS6375385A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02291497A (en) * | 1989-02-10 | 1990-12-03 | Kubota Corp | Vertical shaft pump |
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